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The financial crisis and its economic aftershocks have spawned the first serious examination of the structure of our current banking system and the public policies that have fueled consolidation over the last 30 years and untethered financial institutions from their communities.

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Access to the Internet is an essential infrastructure for any community that cares about economic development, quality of life, and educational opportunities. Unfortunately, most communities are presently dependent on a few unaccountable absentee corporations that act as gatekeepers to...

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Wind and sun are available everywhere, so renewable energy can be economically harnessed at small scales across the country. This nature of renewable energy, and the exponential increase of renewable energy generation, promises to decentralize the nation’s grid system. ...

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At the founding of the American Republic the word “private” had pejorative connotations. Derived from the Latin word “privare”, private meant to divide or tear apart. A privateer was a pirate. The word “public” was an honorable adjective, often...

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ILSR's Waste to Wealth program helps communities across the country create policies and practices that address citizens' environmental concerns and economic needs. We help citizens fight the incinerators and landfills that pollute their air and water, and drive property...

The content that follows was originally published on the Institute for Local Self-Reliance website at http://ilsr.org/does-energy-storage-compensate-thirsty-concentrating-solar-thermal-power-plants/

Concentrating solar thermal power has promised big additions to renewable energy production with the additional benefit of energy storage. But with significant water consumption in desert locations, is the energy storage benefit of concentrating solar enough to compete with the dramatically falling cost of solar PV?

Water consumption can be cut dramatically by using “dry-cooling,” but this change increases the cost per kilowatt-hour (kWh) of power generated from concentrating solar power (CSP). In the 2009 report Juice from Concentrate, the World Resources Institute reports that the reduction in water consumption adds 2-10 percent to levelized costs and reduces the power plant’s efficiency by up to 5 percent.

Let’s see how that changes our original levelized cost comparison between CSP and solar PV. First, here’s the original chart comparing PV projects to CSP projects, with no discussion of water use or energy storage.

To make the comparison tighter, we’ll hypothetically transform the CSP plants from wet-cooled to dry-cooled, adjusting the levelized cost of power.

Using the midpoint of each estimate from Juice from Concentrate (6 percent increase to levelized costs and 2.5 percent efficiency reduction), the change in the cost per kWh for dry-cooling instead of wet-cooling is small but significant. For example, all three concentrating solar power projects listed in the chart are wet-cooled power plants. With a 6% increase in costs from dry cooling and a 2.5% reduction in efficiency, the delivered cost of electricity would rise by approximately 1.7 cents per kWh.

The following chart, modified from our earlier post, illustrates the comparison.

With the increased costs to reduce water consumption, CSP’s price is much less competitive with PV. In our May post, we noted that a distributed solar PV program by Southern California Edison has projected levelized costs of 17 cents per kWh for 1-2 MW solar arrays, and that a group purchase program for residential solar in Los Angeles has a levelized cost of just 20 cents per kWh.

While Nevada Solar One was built without storage, the PS10 and PS20 solar towers were built with 1 hour of thermal energy storage. Let’s see how that changes the economics.

To make the comparison comparable, we’ll add the cost of 1 hour of storage to our two PV projects, a cost of approximately $0.50 per Watt, or 2.4 cents per kWh. The following chart illustrates a comparison of PV to CSP, with all projects having 1 hour of storage (Nevada Solar One has been removed as it does not have storage).

When comparing CSP with storage (and lower water use) to PV with battery storage, we have a comparison that is remarkably similar to our first chart. Distributed PV at a commercial scale (1-2 MW) is still cheaper than CSP, but residential PV is more expensive.

About John Farrell

John Farrell directs the Energy Self-Reliant States and Communities program at the Institute for Local Self-Reliance and he focuses on energy policy developments that best expand the benefits of local ownership and dispersed generation of renewable energy. More